THE EXTRACTION OF THE JUICE BY MILLS 



213 



Bagasse Conveyors. The bagasse is usually conveyed from mill to mill 

 by steel slat endless belts operated by a chain and sprocket drive off a lower 

 roller of the mill. An alternative method employs a scraper conveyor 

 operating in combination with a water-tight trough. 



Strainers. The fine particles of fibre which are carried down with the 

 juice are separated therefrom by brass or copper strainers, the holes in which 

 are usually about i~32nd inch in diameter. The 

 strainer, Fig. 118, is usually arranged as a 

 narrow deep trough, a, parallel with the mill, and 

 is partitioned so as to collect the juices from 

 the various mills separately. Over the surface 

 of the strainers run wooden or rubber-faced 

 scrapers, b, which finally elevate the "cash 

 cush " and discharge it to a screw conveyor, c, 

 running parallel with the rollers, and behind the 

 first mill. This method is indicated in Fig. 118. 



A different type of strainer, operated by the 

 fall of the juice, is shown in Fig. 119. 



Roller Scrapers. The bagasse adheres te- 

 naciously to the rollers, especially those of the 

 later mills. They are kept clean by scrapers, a, 

 arranged as indicated in Fig. 120 ; this method 

 is included in Flower's patent (U.S. 389801, 1888) . FIG. 1 1 7 



The Gearing of Mills. The motion from the ^crankshaft of the cane 

 engine is transmitted to the top roller of a mill, or of a series of mills, by 

 spur and pinion gearing. The limits of the speed of the engines are 35 to 

 55 r.p.m., 45 r.p.m. being very general practice. The train of gearing 

 reduces the number of revolutions in the ratio of from 20 to 25 : I so as to 

 cause the mill rollers to make about 2 revolutions per minute. The 

 train of gearing is now always compound, and such was first used at the 

 beginning of the io,th century. There are still in operation, however, 

 some single trains with the spur wheel as much as 3oft. in diameter. 



FIG. 118 



When two or more mills are connected, the train of gearing may be 

 open or compact. When open, as shown in plan in Fig. 121 for a 6-roller 

 mill, a greater distance is obtained between the units, opportunity thus being 

 given for the application of " bath " maceration. Generally, however, the 

 gearing is arranged as indicated in Fig. 122, as applied to a 9-roller train. 

 In these diagrams, i represents the first motion pinion ; 2, the first motion 



